Antiracing valve for steam-driven feed pumps



March 10, 1953 w. HENKEL 2,630,758

ANTIRACING VALVE FOR STEAM-DRIVEN FEED PUMPS Filed NOV. 4, 1949 BY P05810 ae Ii 14 I |U Wfl T67? SUPPLY ER/CH WHEN/(EL INVENTOR.

14 T TOENE Y Patented Mar. 10, 1953 ANTIRACING VALVE FOR.- STEAM-'DRIVENFEED PUMPS ErichW. HenkeL'Calumet City, 111., assignor to CombustionEngineering-'Super heater,

New York, N. Y.

inc

Application November 4, 1919,.SerialiNo..1'25,41l1

The present invention relates to pumps and particularly to an improvedmeans for preventing racing of a steam driven feed pump when it losessuction.

Steam driven feed water pumps are liable to race or run away in theevent that the water side of the pump becomes air bound or the watersupply fails due to emptying of the supply tank or disruption of pipingconnecting the latter to the pump. The invention contemplates theprovision of a control valve in the exhaust line from the steam cylinderof a reciprocating feed water pump which is subject to water deliverypressure so that it moves towards closed position on loss of pumpsuction and builds up a high exhaust pressure that acts to preventracing of the pump. The invention is also applicable to centrifugalpumps.

In the drawings;

Figure 1 is a diagrammatic view of a pump system embodying the presentinvention; and

Figure 2 is a sectional view on an enlarged scale of the control valveembodied in the system of Figure 1.

In Figure 1 there is represented a conventional reciprocating feed waterpump having one or more steam cylinders I receiving steam through thepiping II and discharging exhaust steam through the pipe [2. Water isdrawn into the water cylinders I3 of the pump from the supply tank [4through a pipe [5 and is forced through the pipe IE to a boiler or otherpoint of use.

In accordance with the present invention there is interposed in theexhaust steam line l2 a control valve designated as a whole by thenumeral 20 in Fig. l. The exhaust steam enters the valve casing 20through the pipe l2 and passing through the valve chamber 23 isdischarged through a pipe 2|. This flow is subjected to control of thevalve member 24 in chamber 23 which in Figure 2 is illustrated as beingseated. This valve member 24 has a by-pass port 25 connecting its inletand outlet sides so that even when the valve 24 is in closed position asmall amount of steam may pass to the vent pipe 22. The stem 30 of valve24 is connected to a pressure responsive diaphragm or bellows 3| locatedin a chamber 32 that is connected by a pipe 33 with the feed line It;leading from the delivery side of the pump. Thus, the bellows 3| issubjected to the water delivery pressure which acts thereon in adirection to open the valve 24 against the resistance of aspring 34located within the bellows. A bypass line 36 connecting with the feedline [6 leads back to the water supply tank It and has a re-' '3 Claims.(GI. 103-15") 'stricti'on 3'! therein. This 'by-p'ass is provided tosafe-guard the operation of the c'on'trolapparatus against a leakyboiler check valve as at 38. The by-pass also serves the useful purposeof eliminating from the water system any air that may have accumulatedwhen the pump is started after a prolonged period of shut down.

Assuming that the pump is applied to a boiler which carries a normaloperating steam pressure of 250 p. s. i. and that the steam flow to thepump through pipe H is regulated automatically by a water regulatorwhich is set to maintain a constant water level in the boiler drum.During normal operation the anti-racing valve 20, 24 in the pump exhaustline will be held in wide open position by the pump delivery pressureacting on bellows 3i. Inasmuch as the valve member 24 in its openposition oifers very little resistance to the flow of exhaust steam, theexhaust steam pressure at the pump will be low or normal. Should a watersupply failure at the water end of the pump occur, which in turn willcause the pump delivery pressure to drop below e. g. p. s. i. for whichthe spring inside the bellows is set, the spring 34 will force the valve24 to its closed position. The steam leaving the pump must then passthrough port hole 25 which will induce a considerable restriction to thesteam flow. It follows that the exhaust pressure between valve 20 andpump, cylinder l9 becomes abnormally high. The pump steam side becomes"steam locked, forcing the pump to run at an idling speed as long asthere is steam entering the pump until conditions at the pump water endare corrected whereupon a water delivery pressure of above 60 lbs. issufflcient to open the valve 24 again. The high exhaust pressure at thepump is immediately released and the pump again is prepared to operateat normal.

What I claim is:

1. In combination with a steam operated pump drawing water from a sourceof supply and introducing it into a feed line provided with a checkvalve, and an exhaust pipe connected to the steam side of the pump; acontrol valve in said pipe; means responsive to a predetermined pressureof water delivered by said pump for opening said valve; spring meansassociated with said valve for moving it to closed position when thewater delivery pressure falls below said predetermined value; and aby-pass associated with said exhaust line and valve for permittingescape of steam to enable continued operation of said pump when saiddelivery pressure falls below said value.

2. In combination with a steam operated pump drawing water from a sourceof supply and introducing it into a feed line provided with a checkvalve, and an exhaust pipe connected to the steam side of the pump; acontrol valve in said pipe; vmeans responsive to a predeterminedpressure of water delivered by said Pump for opening said valve; andmeans operative when said water pressure falls below a predeterminedvalue to act upon said valve so as to restrict the flow of exhaust steamin said pipe and thereby preclude racing of said pump.

3. In combination with a steam operated pump drawing water from a sourceof supply and introducing it into a feed line provided with a checkvalve, and an exhaust pipe connected to the steam side of the pump; acontrol valve in said pipe; pressure responsive means connected to saidvalve arranged whensubjected to a predetermined pressure to move saidvalve in a direction to open it; a pipe connecting said feed line tosaid pressure responsive means for subjecting said means to the deliverypressure of said pump to cause opening of said valve when said pressurereaches a predetermined value; means acting to close said valve; a waterreturn between said feed line and said supply source; and restrictivemeans in said return line for limiting the flow therethrough.

ERICH W. HENKEL.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 1,077,090McGowan Oct. 28, 1913 1,863,406 Hudson June 14, 1932 2,250,865 GrifiinJuly 29, 1941 2,264,753 Henkei Dec. 2, 1941

